newlib: using lwip implementation of interface name/index conversion

Links https://github.com/espressif/esp-idf/issues/3557

components/newlib/platform_include/net/if.h

@@ -15,6 +15,7 @@
 #define _ESP_PLATFORM_NET_IF_H_
 
 #include "lwip/sockets.h"
+#include "lwip/if_api.h"
 
 #define	MSG_DONTROUTE   0x4     /* send without using routing tables */
 #define	SOCK_SEQPACKET  5       /* sequenced packet stream */
@@ -22,8 +23,6 @@
 #define	SOCK_SEQPACKET  5       /* sequenced packet stream */
 #define	SOMAXCONN       128
 
-#define	IF_NAMESIZE     16
-
 #define	IPV6_UNICAST_HOPS   4  /* int; IP6 hops */
 
 #define	NI_MAXHOST  1025